ABSTRACTPhysiological measures—breathing amplitude (BA), breathing cycle time (BCT), galvanic skin response (GSR), skin potential response (SPR), systolic blood pressure (BP), oxygen saturation level (O2S), finger volume (FV), and pulse volume (PV)—were compared with respect to their relative efficiency in discriminating deception in a lie detection experiment. ThirtySs were tested. Stimuli consisted of personal words and neutral words made relevant in the context of a mock crime paradigm. Only GSR, SPR, and FV consistently discriminated better than chance, with GSR and SPR significantly superior to FV. BA and O2S yielded some evidence of discrimination, but were inconsistent across stimulus mater